The new division, known as Clicksmarts, will monitor internet coverage of a brand or a company and engage in online conversations where appropriate.
It will also have the capacity to develop bespoke campaigns using blogging and social media sites.
Richard Nelson, who heads up Clicksmarts, said: "The influence of traditional media has not gone away but there are literally millions of people online with the power to break stories before the traditional media, to champion the brands they love or attack those they dislike.
"As more companies look to develop new markets, the opportunities for them to reach out to their customers in innovative ways through the internet are huge."
Smarts said it hoped the addition of an online PR capability would accelerate the company's growth plans.